Game maker Konami said one of its online portals has been hit by a mass of illicit login attempts, with attackers gaining access to over 35,000 accounts, just days after Nintendo revealed a similar attack on one of its sites.

Konami said that on Monday it noticed a large surge in access errors to its "Konami ID" website, which customers use to create and manage login accounts for other online services run by the company. The game maker said an investigation revealed that from July 13 to June 7, nearly 4 million login attempts were made to the site, with 35,252 successful.

Konami said the login information was probably leaked from a service run by a different company. It said it has frozen the compromised accounts and asked its users to change their passwords.

The accounts include users' actual names, addresses, telephone numbers and email addresses. The IDs can also be used to access some of Konami's other sites in Japan, including an online shopping site, but he company said it had detected no access to paid services using the compromised data.

Konami's announcement comes after Nintendo said last week its "Club Nintendo" website was the victim of over 15 million login attempts. Nintendo's site also has no financial data, but it said attackers gained access to nearly 24,000 accounts containing names, addresses and phone numbers.

Nintendo also surmised that the source of the logins and passwords used by its attackers was a pre-existing list leaked from a different company. Both Nintendo and Konami have asked users to employ separate login details for different services.

Konami, known outside of Japan mainly for game series like Metal Gear Solid and Winning Eleven (also called Pro Evolution Soccer), is also a major maker of arcade and gambling machines.